Exam2 Flashcards
Canine viral diseases
Herpes virus Systematic generalized
- Canine herpesvirus 1: hemorrhagic disease in pups
- Enveloped, dsDNA virus
- Not Very stable in the environment
- Latent infection present w/ serum antibodies
- Dx PCR
- Between 1-3 weeks of age is the highest risk
- Some are zoonotic
Epidemiology
- Present worldwide in domestic and wild dogs
- Seropositive rates >30%
- kennels often have up to ~100% rates of infection
Transmission risk factors
- Direct contact and droplet/aerosol, bodily fluids. Sexually transmitted
- Puppies 1-3 wks of age
- Influenced by the degree of immunity of passive transfer
- 2-4 weeks: mild to asymptomatic
- > 4 wks: occasional disease
- > 6 mts: rare
- High mortality rate, most puppies die within 24-48 hrs after onset of clinical signs
- Painful crying
Diagnosis necropsy
- Disseminated focal necrosis and hemorrhage of multiple organs
- Splenomegaly
- Diffuse lymph node enlargement
- CNS lesions
Canine Herpes in Adult dogs
- Respiratory infection w/ mild runny nose or cough
- Reproductive infection may cause vesicles or pustules of the vagina or prepuce, discharge, vaginitis, decreased fertility, abortion, stillbirth puppies.
- Most infections remain asymptomatic.
- Once infected, usually remains infected and stress symptomatic
- Excretions from respiratory and reproductive tract contagious
Diagnosis
- History and clinical signs of puppies
- Viral culture: swabs from vagina, preputial, respiratory secretions
- Organs of dead fetuses
- Histopathology: intranuclear inclusions
- Serology and clinical signs
Supportive therapy
- Prognosis is poor for puppies at birth or those 1-3 weeks of age.
- Survival accompanied with permanent damage to multiple organs
Prevention
- No vaccine in US
- Infected bitches develop antibodies.
- Removal of puppies via C-section
Pseudorabies in dogs (Herpesvirus)
Pseudorabies aka Mad itch, Aujezsky’s Disease
- Associated with hunting of feral pigs or feeding infected meat to dogs
- Relatively common in Southeastern US
- Wild pigs are reservoir
Clinical signs
- Frenzy associated with intense pruritus
- Paralysis of the jaws and pharynx
- Drooling, salivating, howling
- Signs that simulate rabies, however no tendency to attack humans or other animals
Adenoviruses
- dsDNA viruses
- Very resistant in the environment
- Wide range of clinical presentations
- Diagnosis confirmed by viral isolation and PCR
- Transmission direct contact, droplet/aerosol
- Virus is used as a vaccine vector
Canine hepatitis
- Type 1
- Type 2 canine tracheobronchitis more important
Canine Infectious tracheobronchitis (Kennel cough)
- Bordetella bronchiseptica
- Canine parainfluenza virus
- Canine distemper virus
- Serotype 2 Canine Adenovirus (CAV-2) often acting in concert
- *Kennel cough is the most prevalent problem of upper respiratory airways in dogs. Now referred to as Canine Infectious Respiratory Disease Complex (CIRDC)
Diagnosis of CAV-2
- Dry hacking cough
- Loss of appetite and lethargy in more severe cases
- Fever, productive cough, possible vomiting and diarrhea
- Definitive Dx: viral isolation from bronchial epithelium (large intranuclear inclusion bodies)
Treatment
- virus runs its course
- Isolation of pet
- Cough suppressants should not be used
- Antibiotics only when needed
- Vaccination generally combined ex: Vanguard Plus 5
- Zoetis Vanguard intranasal: CAV-2, CPiV, Bordatella bronchiseptica
Infectious canine hepatitis
- *Rarely seen in US domestic dogs
- Sudden death form: confused with poisoning
- Severe: bleeding gums, bloody diarrhea w/ vomiting, shock or coma. Death occurs 3-5 days after onset of clinical signs.
- Moderate form: there is depression, lethargy, abdominal pain and distention. **Corneal opacity “blue eye” from the immune response
- Can also occur in wild foxes and cause encephalitis
- Virus shed in bodily fluids, ingested or inhaled. It travels to tonsils and regional lymph nodes, then liver, kidney, and other organs where it replicates.
- Risk of blue eye reactions from vaccine
- No longer type 1 vaccine bc type 2 covers both
- Maintaining good hygiene will help to prevent spread
Canine Warts (papillomavirus)
- mostly affects young dogs
- Primarily in the mouth
- Very florid (multi-shaped)
- May induce cancer, may require surgery
- Do not cross species
- “typing” is established through sequencing nor serology
- Has been associated with carcinomas (squamous cell) and are studied as human models of cervical cancer
Canine Parvovirus
Disease
-Generalized neonatal disease, enteritis, myocarditis, panleukopenia
Virus
- Very resistant in environment and disinfectants
- Severe disease and death in young animals
- Can cause abortion and fetal abnormalities
- Transmission by contact and fomites
- ELISA, PCR. Difficult to isolate in culture
- Dependoviruses have been used for gene therapy in humans
Clinical signs
- Puppies <6 mts most susceptible
- Incubation period 2-5 days
- Rottweiler, Dobermans, Labradors, American Staffordshire Terrier, German Shepherds, Alaskan Sled dogs.
- Highly resistant virus in environment or inanimate object
- Fever, depression, dull, sleepy, not interested in anything.
- Anorexia, loss of appetite, vomiting, diarrhea ~2 days PI.
Myocarditis in puppies
- CPV2 first appear, it was common 1970’s
- CPV death results from myocarditis, 3-8 up tp 16 weeks of age
Historical parvoviruses
-Mutations FPLV transferrin receptor type-1
-CVP2c 2021 prevalent
-Canine parvovirus type 2 first confirmed in 2006. Outbreaks of disease associated with CPV-2b also continue to be reported.
-Canine CPV1 was discovered many years before CPV2
and is not pathogenic
Vaccine
- MLV protection against all strains
- Based on CPV-2b
- Ability to override maternal antibodies
- **Bleach 1/30 parts water would disinfect
Coronaviruses
- Infect a wide range of species
- In poultry: bronchitis
- In swine: transmissible gastroenteritis (TGE) and porcine epidemic diarrhea (PED)
- In dogs, cattle, horses: mild enteritis and mild respiratory disease
- In cats: infectious peritonitis (FIP)
- Humans SARS-Cov-2
Enteric Coronavirus
- Widely recognize around the world causes mild enteritis
- AS a co-infection exacerbate infection with CPV-2c.
Prevention and control
- Vaccination
- Transmission via contact, oral secretions or contact with feces.
- Fairly resistant and can remain infectious for several days outdoors and frozen temperatures
- Dogs that frequent dog shows, boarding facilities should be vaccinated.
Paramyxoviruses
Cause:
- Canine influenza virus 5 (SV5) respiratory disease
- Canine Distemper virus: related to Rinderpest and Measles.
- Not common in US household dogs, but common in shelters
Characteristics of Paramyxoviruses
- Virus is not stable in environment and INACTIVATED by HEAT, sunlight, most detergents, soaps, and various chemicals.
- Respiratory and systematic clinical presentations
- Diagnosis confirmed by ELISA, PCR, or virus isolation
- Transmission by direct contact and droplet
- *Attacks respiratory tract, CNS, and GI tract.
- *Most common cause of seizures in dogs >6mts
- Immunosuppression is the predominant effect of infection.
Clinical signs
- Do not appear right away. Fever after incubation ~7 days.
- Most common onset of illness: 2-5 weeks PI
- Conjunctivitis (inflammation of the eyelids) and discharge
- Nasal discharge
- Bronchitis: upper airways
- Gastroenteritis
- Vomiting, diarrhea
- Neurological signs: Gum smacking, head pressing, incoordination, poor balance, CHOREA (muscle tremors)
- Nystagmus (uncontrolled eye movement)
Pathogenesis
- Shed in all bodily excretions
- Transmission: aerosol, droplet.
Diagnosis
- Signs of distemper can be extremely variable depending on the stage of the disease.
- PCR
- Antibody titers and check for IgM
- Post-mortem immunochemistry on tissues
Treatment
- Supportive care
- Keep eyes and nose clean free of discharge
- Give broad-spectrum antibiotics
- Discontinue water and food if patient if vomiting and diarrhea
- Bronchodilators
- Neurological symptoms: Glucocorticoid therapy can help optic neuritis. Anticonvulsant drugs-recommended at the beginning before seizures develop
- *Long term problems: lasting seizures, change in footpads, tear deficiency, damage to retina
Vaccination
- Nobivac
- Important for all puppies MLV
- Many formulations available
- Still present in most areas and hard to treat
- Annual vaccination 1 dose recommended
Canine Influenza
- 2015 Chicago H3N2
- Influenza A: 6-8 segments, defective interfering particles genetic re-assortment occur frequently
- Relatively unstable in environment
- Predominantly cause respiratory disease but sometimes systematic
- Antigenic drift and shift
- Dx ELISA, PCR, or virus isolation
- Transmission by direct contact, fomites, droplet infection.
Interspecies of Influenza virus
-Poultry H1-H13 sporadic to enzootic
-2006-2015 Dog H3N8
-2004 Equine H3 (H7) enzootic transmission to dogs in FL
H: hemagglutinin
N: Neuraminidase. Both surface proteins that cause immune response. All present as subclinical enteric infections in wild birds.
Canine H3H8 clinical signs
- Hemorrhagic pneumonia and death
- Acute disease, fever, nasal discharge, cough that persists for several days
Epidemiology
- Racing kennels or shelters spreads rapidly
- Transmission by contact, fomites, aerosols.
- Possible origin of virus: horse meat infected fed raw to racing dogs.
- 2015 H3H2 Chicago, Chinese or South Korean strain longer excretion 10-15 days
Diagnosis
- PCR
- Virus Isolation
- Swabs refrigerated after collection and sent overnight
- Antibody testing serum sample 10-14 days apart
Vaccination as needed basis
- Zoetis vaccine
- Not a core vaccine
Antiviral
-Tamiflu, but not recommended
Rhabdoviruses
Genuses:
- Lyssaviruses (neurological)
- Vesiculovirus (epithelial)
- Ephemerovirus
Characteristics
- Unstable in the environment
- Wide range of clinical presentations
- Many Serotypes
- Confirmation Dx Immunofluorescence or PCR
- Transmission: direct contact, droplet, mechanical/biological vector, arthropods.
Rabies
- Preventable
- CNS disease
US Variants
- Raccoon (Eastern US)
- Fox, Skunk, Mongoose
- Bats
Clinical signs
- Hypersensitivity to stimulus
- Hydrophobia
- Blood in vomit
- Hypersexuality
- Virus shedding possibly 2-3 days before clinical disease develops
- *Furious: limbic system
- *Dumb: neocortex
Diagnosis
-Viral antigen detected by immunofluorescent antibody staining
Prevention
- Vaccine at 3 months, boost at 1 year, then very 3 years after that
- Cattle, horses: vx every year
Canine Core vaccines
- Distemper (MLV)
- Parvovirus (MLV)
- Adenovirus-2 (MLV)
- Rabies (Killed)
Non-core vaccines
Distemper-measles B. bronchiseptica Leptospirosis spp. rLyme (OspA) Lyme-killed Crotalus atrox Porphyromonas spp.
Not recommended
CAV-1 Giardia Parvovirus (killed) Adenovirus-2 (killed) Coronavirus-MLV Coronavirus-Killed
Viral diseases of Cats
Poxvirus in Cats
- Cowpox is a foreign animal disease, not present in US
- Has ability to infect many species, including rodents and cats.
Characteristics
- Resistant to environment
- Lesions proliferate and some “tumor like”
- orthopoxiviruses and Capripoxviruses induce long lasting immunity
- Diagnosis by clinical appearance and electron microscopy or virus isolation
- Transmission by contact and mechanically arthropods
- Several are zoonotic
Cowpox in domestic cats
- Never seen in US
- Infection associated with fever in cheetahs frequently fatal.
- Acquired from bank voles, subclinical infection
- Zoonotic
Diseases cause by Herpesvirus
- Feline upper respiratory Conjunctival Disease Complex
- Pseudorabies (Aujeszky’s disease, Mad itch disease) not as important
- Feline Herpesvirus 1, feline rhinotracheitis
Characteristics Herpesvirus
- Unstable in environment
- latent infections
- PCR confirmatory Dx
- Transmission direct contact, droplet/aerosol
- Some zoonotic or cross species
Feline Upper Respiratory-Conjunctival Disease
- Herpes and Calici viruses along with Chlamydia trachomatis
- Erroneously called feline cold or influenza
Diagnosis
- Fluorescent stain of cornea to identify ulcerations
- Take corneal/conjunctival swab, transfer to microscope slide for special Ag detection
- Virus isolation in cell culture
- PCR
Feline Viral Rhinotracheitis (FVR)
- Rhinitis and pharyngitis is most common in the 8-14 week range
- Conjunctivitis and dendritic ulcers
- Chronic sinusitis may develop
- Oral/nasal transmission
- Kittens may develop severe systematic disease 2-4 wks, and die
- Carrier queen may have abortions
Caliciviruses
-Resistant to environment and many disinfectants
-Noravirus in humans
-Chronic infection occur in the cat
-Dx PCR, difficult to isolate in culture
-Transmission by contact and fomites
Respiratory type:
-Cell tropism
-Tongue, gingiva, and hard palate ulcers predominate other areas including nasal cavity, pinnae.
-Palatine ulcer, Tongue ulcer
Lymphoreticular type:
-Affects kittens at 4-10 weeks of age, causing limping, stiffness, soreness, and fever.
-Cell tropism: splenic reticuloendothelial tissue and synovial tissue
Virulent systemic (VS)
-1998 CA
-‘Spectacular outbreaks”
-Fomites transmission
-Respiratory disease progresses to endothelial cells causing vascular injury
-Submandibular and limb edema
-Temp >106F
-Dermatitis
-60% of adults can die
Diagnosis of Feline respiratory disease
- virus isolation
- Swabs oropharyngeal mucosa, external nares, and conjunctival sacs are preferred.
- **Virus shed intermittently, difficult to diagnose
Control Respiratory Disease
- FVR MLV
- Good management Clorox 1/30 important
Differentiation of Feline Upper Respiratory Conjunctival Disease Complex
Clinical Guide:
- Chlamydia and mycoplasma conjunctivitis
- Herpesvirus: conjunctivitis, rhinitis, pharyngitis, oral ulcers
- Calicivirus: oral ulcers only or pneumonia
- **Test for all three and figure it out from there
- ** Vaccines aim to reduce severity of clinical disease
Pseudorabies in cats
- Probably acquired from eating aborted infected swine fetuses
- Seen in farms prior to the eradication program
- Pseudorabies still present in feral swine and panthers.
Feline Parvovirus
-Generalized disease in kittens, panleukopenia, enteritis, cerebellar hypoplasia.
Characteristics of virus
- Very resistant to environment and disinfectants
- Replicates only in dividing cells
- Disease and death in young animals
- Can cause abortion or fetal abnormalities
- ELISA, PCR. Virus difficult to isolate in cell culture.
- Transmission by contact and fomites
Feline Panleucopenia Clnical presentation
- Lathergy, anorexia, vomiting of yellow fluid. Act thirsty but usually won’t drink
- High fever >40C
- Diarrhea yellowish, blood-tinged
- Pregnant cats may abort
- FLP is now rarely seen as vaccination has been very effective
- Ataxia if affected during birth, hypoplasia (uncoordinated movement)
Diagnosis
- Care test kits IDEXX, Agen, Synbiotics for detection of antigen in feces.
- False negatives can occur due to intermittent shedding
- Best test 5 days after onset of clinical signs
- *CVP-2b has been reported to cause ‘panleukopenia-like’ disease in cats
Prevention and control
- Vaccination MLV
- Highly resistant virus
- Disinfection with bleach effective
- Shelter management: some false positives due to recent vaccination
Retrovirus Diseases
- Gammaretrovirus (FeLV)
- Lentivirus (FIV)
- Prevalence only ~2% in healthy cats, 30% in high-risk or sick cats
- Unstable in environment
- Chronic disease characterized by prolonged nature and immune compromise
- Persistent infection
- Transmission by direct contact or iatrogenic
- **Key feature, ability to acquire and alter host-derived genetic sequences.
Diagnosis
-ELISA, PCR, Serology, virus isolation difficult.
Clinical disease FeLV
- Feline leukemia virus: affects the cat’s body in many ways. It is the most common cause of cancer in cats (lymphoma). It may cause various blood disorders.
- May lead to inability to protect itself against other infections
- During the early stages of infection, it is common for cats to exhibit no signs of disease at all. However, over months or even years, recurrent illness, persistent diarrhea, weight loss, poor coat condition, pale gums, seizures, abortion of kittens.
Pathogenesis
- Queen to kittens
- Cats to other cats via saliva, urine, milk.
- Viremia: virus shed in saliva, milk, nasal secretions, feces, urine.
- Targets lymphoid organs (thymus, spleen, lymph nodes)
- Immune response unable to clear infection
- Infection type: Progressive infection, Regressive infection
- virus replicates in lymph nodes and bone marrow.
Diagnosis
- PCR
- SNAP FIV/FeLV combo test
- Antigen P27
Transmission
- vertical before and after birth
- Cat to cat close contact
- Saliva most efficient, urine, Iatrogenic
- Age resistance to FeLV: adults relatively resistant to infection
- 70% of 3 mts old kittens become infected, experimental infection difficult >4 mts of age.
Cancer FeLV epidemiology
- Decreased prevalence
- Culling from shelters
- Vaccination
- In-house testing
- Changed lymphoma type
- Exact reason not known
- **Although vaccines are available for both viruses, identification and segregation of infected cats form the cornerstone for preventing new infections
Vaccine
-1985 first
-May not prevent transient infections
-Two-dose series then annual boosters
-Not AAFP core vaccine for pets
-Implicated in vaccine-associated sarcoma
-FeLV adjuvants driven response for sarcomas
New vaccines
-Purevax: no adjuvants
** Development and use of canarypox vectored recombinant vaccines reduces vaccine induced sarcomas and other vaccine pitfalls
Viral diseases of Cats II
Most important:
- Feline calicivirus infection
- Feline viral rhinotracheitis
- Feline immunodeficiency infections
- Feline coronavirus infections
- Feline leukemia
Feline Immunodeficiency virus
- Lentivirus (retrovirus)
- Evolved from exotic cats
- Spread to cats more than 1,000 years ago
- 1986 cats with AIDS
- Testing 1987, vaccine 2002, but not DIVA compatible
Pathogenesis FeLV vs. FIV
FeLV: vertical and horizontal. Virus shed in secretions, feces, milk and urine. Targets lymphoid organs. Immune response unable to clear infection. Lymph node, bone marrow.
FIV: bite wounds, horizontal. High concentration in saliva. Drop lymphocyte count, inversion of T-lymphocyte ratio CD4/CD8. Immune response unable to clear infection. More horizontal
Clinical Syndromes Associated with FIV
- Lymph nodes: enlarged
- Eyes: Uveitis, dementia, seizures, ataxia (CNS).
- Immunosuppression: Stomatitis and gingivitis, neoplasia
Stomatitis: most common FIV sign, also occurs in FeLV
- Late stage event
- Calicivirus commonly isolated
FIV prevalence and transmission
- 80% fighting bite wounds transmission, male toms
- Queen to kittens transmission is rare
- Risk factors: male, outdoors access, adulthood
- Iatrogenic: needles, instruments, transfusions
Diagnosis
- Detection of antibody
- SNAP test
- Peak viremia, not antigen test because it falls during asymptomatic stage
- **FeLV and FIV are unstable in the environment
- **Disinfectants are effective
AAFP Concerns Over Vaccination
- Not DIVA compatible
- Vaccine induced antibodies can persist for more than 4 years in some cats
- Vaccinated should be permanently identified and history included in microchip database
- Testing cats prior to vaccination is essential to ensure negative status.
- *Remove from market in 2017
Worldwide Distribution
- 27 felids species identified. Lion 76%
- Phylogenetic analysis of FIV proviral sequence endemic…. quite infrequent today though.
100 days survival rate
- FeLV 47% at 3 years vs. FIV 94% at 3 years
- survival influenced by selective euthanasia
Summary FeLV and FIV
- Both retroviruses with global impact
- FeLV can cause tumors (lymphoma mostly), bone marrow suppression syndromes (mainly anemia) and lead to secondary infectious diseases cause by suppressive effects of the virus. It is more pathogenic than FIV, considered responsible for more clinical syndromes than any other agent in cats. Less commonly diagnosed today than 20 years ago. Decreased prevalence
- FIV: acquired immunodeficiency disorder that increases opportunistic infections, neurological disease, and tumors.
- In most naturally infected cats it itself does not cause severe clinical signs, may live for years without health problems.
- *2% in healthy cats and 30% in high-risk cats
Rhabdoviruses
- More cats diagnosed with rabies than dogs
- Cats can be infected with rabies by contact with raccoons or bats that are infected.
- TN 2003, 4 cases
Clinical signs
- Loss of appetite, anxiety
- Infection of the limbic system (hypothalamus, hippocampus, amygdala)
- Restlessness, wandering, Hypersensitivity to stimulus, most commonly presents as “dumb rabies”
Vaccines
- @ 3 mts, boost @ 1 year, every three years. High-risk may need yearly boosters.
- Recombinant canarypox available for cats
